Subject Re: [firebird-support] "EXTRACT (YEAR FROM DT.DATA) <= 2016" or "DT.DATA <= '12/31/2016'"
Author Louis Kleiman
You can create an expression index on EXTRACT (YEAR FROM DT.DATA) to get performance improvements in your first expression, but an index on plain ol' DT.DATA would be more flexible -- it would provide assistance in more cases than the expression index. The plain ol' column index would speed up the DT.DATA <= '12/31/2016', but not the EXTRACT... expression.

As always in our business, tradeoffs...

On Fri, Dec 9, 2016 at 12:12 PM Luigi Siciliano luigisic@... [firebird-support] <> wrote:

Il 09/12/2016 15.47, Mark Rotteveel mark@... [firebird-support] ha scritto:


Could you please put all pertinent information of your question in the
body, and not only in the subject. It makes questions a lot easier to
read (especially on mobile devices).

I'm sorry, I rewrite the question:

  what is more performant: "EXTRACT (YEAR FROM DT.DATA) <= 2016" or "DT.DATA <= '12/31/2016'"?

I would prepare myself for a table that grows rapidly.

Is the same in FB 2.5.6 or 3.0.1?


Luigi Siciliano